Packaging bag, especially for cooked ham, provided with drain valve
DESCRIPTION OF INVENTION 
     At present, the meat used for production of cooked ham is subjected to a cooking and shaping process in suitable metal molds, from which the meat chunk is removed after adequate cooling and introduced in a packaging before being passed on to the further processing phases. 
     According to a manufacturing process which is the subject matter of a patent application filed by the applicant, is adopted a packaging bag apt to allow the cooking of the meat to produce the cooked ham in the packaging bag itself. 
     For this purpose, the packaging bag must be suitable to allow drainage of the liquefied fat and other liquids. According to this patent, in order to permit the fat to escape, the invention contemplates the use of a heat weldable material packaging bag provided, on at least one of its walls, with a hole, at which is secured to the wall of the bag a drainage valve inside the bag itself. This valve consists of a disc equipped with suitably spaced projecting ribs apt to permit to secure the disc to the bag wall, for example, by thermo welding in such manner that the center of the disc matches with the center of the drainage hole. The invention will now be explained, in conjunction with the annexed drawings which illustrate by way of example and non limitedly a preferred embodiment of the disc acting as a drainage valve. 
    
    
     In the drawing 
     FIG. 1 is a view in cross section of a wall of the bag, to which the drainage valve according to the invention is applied. 
     FIG. 2 is a view of the drainage valve taken on lines II--II of FIG. 1; 
     FIG. 3 is a cross section, taken on lines III--III of the drainage valve FIG. 2. 
    
    
     According to FIG. 1, the bag identified by integer 1 comprises walls 4 made of heat weldable material, at least one of said walls being provided with a hole 6 apt to permit drainage of the liquified fat and other liquids developed during the cooking phase of the meat (not shown) contained in the bag itself. 
     A drainage valve 10 is applied on the internal surface of wall 4 of the bag (FIGS. 2 and 3); said drainage valve consists of a disc made of plastic material, the surface 11 of which, facing the wall of the bag, is provided with a plurality of radial projecting ribs 12 as well as radial grooves 14 and circular grooves 16,17 which intersect said radial grooves. 
     Radial grooves 14 lead into an annular collecting recess 18 delimiting a central circular zone 20, preferably slightly convex, the apex of which is located substantially at the same level of surface 11 of the disc. Said disc is provided, on its other side 22 opposite the annular recess 18, with a cylindrical raised part 24. 
     The application of the drainage valve to bag wall 4 is achieved preferably by heat welding of the wall itself on the spaced radial raised ribs 12. 
     In this way, the wall 4 remains detached from disc surface 11 for the remaining part and the fat, fluidized by the heat, can flow partially between wall 4 and surface 11 itself in the zones comprised between said raised ribs 12, particularly through grooves 14 communicating with collecting groove 16 and 17, and collecting in annular recess 18 from where it flows out through hole 6 provided in the wall, as shown by the arrows in FIG. 1. At the end of the cooking phase, the bag containing the cooked ham is removed from the mold and the part of the wall surrounding the hole 6 is thermo sealed to the center zone 20 of the disc. 
     The advantages afforded by the adoption of a bag provided with drainage valve, avoiding any contact with the meat after cooking and any contamination, are evident.